The present invention relates to a color key, especially as an aid for selecting the proper color of artificial teeth and as a communication means for restorative dentistry, wherein the color key comprises a plurality of insert members to be inserted into a base and having at their ends a respective sample element.
Such color keys are known from U.S. Pat. No. 5,643,589. Such color keys have been successively used in practice for the purpose of providing flexibility with respect to color selection and patient-specific individualization but also with respect to different focal points of different dental practices and dental labs.
With respect to increased requirements regarding natural appearance of artificial teeth it is desirable to provide color keys which provide improved reproducible results by direct comparison with the present natural teeth and an esthetically improved restoration result.
In this context a plurality of color keys are known. An example of such a color key is known from German Offenlegungsschrift 34 29 927. In this color key, the support elements are removably attached and between the support element and the dental material an opaque layer is arranged so that the color and structure of the support element is not visible through the dental material.
Furthermore, it has been suggested to provide a plurality of bases for the support elements that are then detachably connected to one another. In this solution the two bases can be positioned in various orientations to one another.
Each insertable element can be removed from the known color key so that basically a comparison between the natural and artificial teeth is possible by placing the insert element with the sample tooth adjacent to the natural tooth. In most cases, the insert element, for reasons of available space, and the lip area of the patient must be placed at a slant adjacent to the natural tooth so that due to the different light exposure of the artificial tooth and natural tooth a different visual effect will result. Only a few patients are able to visualize and compensate the differences so that the actual color that was determined by the color key will often deviate from the desired result.
Even though it is known that for proper visual matching the use of indirect natural light is optimal, the optimal illumination situation cannot be realized or realized only with difficulty in different dental practices or dental labs, especially since in most cases artificial light sources are used which provide proper illumination for other work to be performed in the dental practice or dental lab.
Even when using identical spectral photometric curves, same sample elements always appear differently when a textured or structured sample element is compared to a smooth or planar surface.
In the so-called painting technique used in wide areas of tooth restoration, it is common to employ colors which differ greatly from the main dental material. It is also desirable to evaluate such colors which, however, has not been possible in the past with known color keys. This is also true for color nuances used for dental materials for the neck of the tooth and for transparent materials.
It is therefore an object of the present invention to provide a color key of the aforementioned kind which allows for an improved evaluation during selection of an artificial tooth including its nuances and is less sensitive with respect to different illumination situations.